Liquid crystal display device

ABSTRACT

A pair of electrodes which constitute an upper layer and a lower layer with respect to an interlayer insulation film are formed as different layers at respective pixel regions on a liquid-crystal-side surface of one substrate out of respective substrates which are arranged to face each other in an opposed manner by way of liquid crystal. At two pixel regions which are selected from the respective pixel regions, the height of background layers on which the electrodes which constitute the lower layers with respect to the interlayer insulation films are formed differs with respect to a surface of one substrate. The film thickness of the interlayer insulation film is set small with respect to the high background layer out of respective background layers which differ in height and is set large with respect to the low background layer out of respective background layers which differ in height.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a liquid crystal display device,and more particularly to a so-called lateral electric field type liquidcrystal display device.

[0003] 2. Description of the Related Art

[0004] In a so-called lateral electric field type liquid crystal displaydevice, on each pixel region on a liquid-crystal-side surface of onesubstrate out of respective substrates which are arranged to face eachother in on opposed manner by way of liquid crystal, a pixel electrodeand a counter electrode which generates an electric field between thepixel electrode and the counter electrode are formed, and the lighttransmittance of the liquid crystal is controlled by components of theelectric field substantially parallel to the substrates.

[0005] In such a liquid crystal display device adapted to an activematrix type, on the liquid-crystal-side surface of the above-mentionedone substrate, regions which are surrounded by gate signal lines whichare extended in the x direction and are arranged in parallel in the ydirection and the drain signal lines which are extended in the ydirection and are arranged in parallel in the x direction are formed aspixel regions, and a switching element which is operated in response toscanning signals from the gate line, a pixel electrode to which videosignals are supplied from the drain signal lines through the switchingelement and a counter electrode which is arranged in a spaced-apartmanner from the pixel electrode are formed on each pixel region.

[0006] Then, in performing the color display, there has been known aliquid crystal display device having the structure in which colorfilters are formed on the above-mentioned one substrate side and thecolor filters are not formed on the other substrate side. Such astructure is devised to reduce the influence of the displacement ofalignment of the other substrate to one substrate to cope with therecent demand for high definition.

SUMMARY OF INVENTION

[0007] However, in the liquid crystal display device having such aconstitution, the layer thickness is not made uniform over all colorfilters of red (R), green (G) and blue (B).

[0008] Such a situation occurs when the layer thickness of respectivecolor filters are intentionally set to different values to attain thebalance of transmittance or color purity among respective color filtersof R, G and B or when the layer thickness is not made uniform over allcolor filters of red (R), green (G) and blue (B) due to theirregularities in manufacturing the color filters.

[0009] In these cases, when the pixel electrodes and the counterelectrodes are formed by way of an interlayer insulation film on upperlayers of the color filters, the height of the interlayer insulationfilm with respect to a surface of one substrate is reflected on thelayer thickness of the color filters so that the respective heights ofthe pixel electrodes or the counter electrodes (heights from the surfaceof one substrate) differ.

[0010] This makes the layer thickness of the liquid crystal atrespective pixels non-uniform so that the equal light transmittancecannot be obtained with respect to the respective color pixels.

[0011] Further, when the interlayer insulation film which is interposedbetween the pixel electrodes and the counter electrodes is made of resinmaterial or the like which is formed by coating, the thickness of theinterlayer insulation film differs depending on the respective pixels ofdifferent colors. Accordingly, the voltage drop which differs dependingon the interlayer insulation film between the pixel electrodes and thecounter electrodes displaces brightness-voltage characteristics thusleading to the collapsing of the color balance of the intermediate grayscale.

[0012] The present invention has been made in view of thesecircumstances and it is an object of the present invention to provide aliquid crystal display device which can enhance the display quality.

[0013] To briefly explain the summary of the typical inventions amongthe inventions disclosed in this specification, they are as follows.

[0014] Means 1.

[0015] A liquid crystal display device according to the presentinvention is, for example, characterized in that:

[0016] a pair of electrodes which constitute an upper layer and a lowerlayer with respect to an interlayer insulation film are formed asdifferent layers at respective pixel regions on a liquid-crystal-sidesurface of one substrate out of respective substrates which are arrangedto face each other in an opposed manner by way of liquid crystal,

[0017] at two pixel regions which are selected from the respective pixelregions, the heights of background layers on which the electrodes whichconstitute the lower layers with respect to the interlayer insulationfilms differ with respect to a surface of one substrate, and

[0018] the film thickness of the interlayer insulation film is set smallwith respect to the high background layer out of the respectivebackground layers which differ in height and is set large with respectto the low background layer out of the respective background layers.

[0019] Means 2.

[0020] A liquid crystal display device according to the presentinvention is, for example, characterized in that:

[0021] a pair of electrodes which constitute an upper layer and a lowerlayer with respect to an interlayer insulation film are formed on atleast color filters as different layers at respective pixel regions on aliquid-crystal-side surface of one substrate out of respectivesubstrates which are arranged to face each other in an opposed manner byway of liquid crystal from the one substrate side,

[0022] at two pixel regions which are selected from the respective pixelregions and on which two color filters of different colors are formed,the heights of surfaces of the color filters differ with respect to asurface of one substrate, and

[0023] the film thickness of the interlayer insulation film is set tosatisfy a following formula (1).

[0024]0<film thickness difference of the interlayer insulation filmbetween pixel regions

<film thickness difference of the color filters between pixelregions  (1)

[0025] Means 3.

[0026] A liquid crystal display device according to the presentinvention is, for example, characterized in that:

[0027] a pair of electrodes which constitute an upper layer and a lowerlayer with respect to an interlayer insulation film are formed on atleast color filters as different layers at respective pixel regions on aliquid-crystal-side surface of one substrate out of respectivesubstrates which are arranged to face each other in an opposed manner byway of liquid crystal from the one substrate side,

[0028] at two pixel regions which are selected from the respective pixelregions and on which two color filters of different colors are formed,the heights of surfaces of the color filters differ with respect to asurface of one substrate, and

[0029] the film thickness of the interlayer insulation film is set tosatisfy a following formula (2).

[0030] ¼×film thickness difference of color filter between pixel regions

[0031] <film thickness difference of interlayer insulation film betweenpixel regions,

<¾×film thickness difference of color filter between pixel regions  (2)

[0032] Means 4.

[0033] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of the means 2 or3, characterized in that the film thickness of the interlayer insulationfilm is set to satisfy a following formula (3).

[0034] film thickness of interlayer insulation film

<{fraction (3/2)}×times film thickness of thickest color filter  (3)

[0035] Means 5.

[0036] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of the means 2 or3, characterized in that the film thickness of the interlayer insulationfilm is set to satisfy a following formula (4).

[0037] {fraction (1/4)} times film thickness of thinnest color filter

[0038] <film thickness of interlayer insulation film

<{fraction (3/2)} times film thickness of thickest color filter  (4)

[0039] Means 6.

[0040] A liquid crystal display device according to the presentinvention is, for example, characterized in that:

[0041] a pair of electrodes which constitute an upper layer and a lowerlayer with respect to an interlayer insulation film are formed asdifferent layers at respective pixel regions on a liquid-crystal-sidesurface of one substrate out of respective substrates which are arrangedto face each other in an opposed manner by way of liquid crystal,

[0042] at the respective pixel regions, the heights of background layerson which the electrodes which constitute the lower layers with respectto the interlayer insulation films are formed differ with respect to asurface of one substrate, and

[0043] the film thickness of the interlayer insulation film is set smallwith respect to the high background layer out of the respectivebackground layers which differ in height and is set large with respectto the low background layer out of the respective background layerswhich differ in height.

[0044] Means 7.

[0045] A liquid crystal display device according to the presentinvention is, for example, characterized in that:

[0046] at respective pixel regions on a liquid-crystal-side surface ofone substrate out of respective substrates which are arranged to faceeach other in an opposed manner by way of liquid crystal,

[0047] a pair of electrodes are formed by way of a protective film whichis formed by sequentially laminating a first protective film and asecond protective film,

[0048] the respective electrodes are arranged in a spaced-apart mannerin a plan view so as to generate an electric field between theelectrodes,

[0049] the relationship between the film thicknesses d₃, d₂ of the firstprotective film and the second protective film on the electrode arrangedas a layer below the protective film and the film thicknesses d₃′, d₂′of the first protective film and the second protective film on a regionbetween the pair of electrodes satisfies a following formula (5)

d ₃ ≡d ₃ ′, d ₂ <d ₂ ′<d ₂ +d ₄  (5),

[0050] and

[0051] the relationship between the layer thickness d₁ of liquid crystalon the electrode arranged below the protective film and the layerthickness d₁′ of the liquid crystal on the region between the pair ofelectrodes satisfies a following formula (6).

d ₁ ≡d ₁′ (here, d ₁ ≦d ₁′)  (6)

[0052] Means 8.

[0053] A liquid crystal display device according to the presentinvention is, for example, characterized in that:

[0054] at respective pixel regions formed on a liquid-crystal-sidesurface of one substrate out of respective substrates which are arrangedto face each other in an opposed manner by way of liquid crystal,

[0055] a pair of electrodes are formed by way of a protective film whichis formed by sequentially laminating a first protective film and asecond protective film,

[0056] the respective electrodes are arranged in a spaced-apart mannerin a plan view so as to generate an electric field between theelectrodes, and

[0057] in two selected pixel regions, assuming the film thickness of thefirst protective film in one pixel region as X₃, the film thickness ofthe second protective film in one pixel region as x₂, the film thicknessof the first protective film in the other pixel region as y₃ and thefilm thickness of the second protective film in the other pixel regionas Y₂, a following formula (7) is established.

X ₂ +X ₃ ≡Y ₂ +y ₃ , X ₃ >y ₃ , X ₂ <Y ₂  (7)

[0058] Further, when the distance from the substrate to the liquidcrystal layer differs, the thickness of the liquid crystal layerdiffers. In the lateral electric field method, the driving voltagedepends on the thickness of the liquid crystal layer. That is, thethicker the liquid crystal layer, the same brightness can be obtainedwith the lower voltage. On the other hand, this implies that a B-V curvediffers between two pixels where the distance from the substrate to theliquid crystal layer differs from each other and hence, the same grayscale cannot be displayed using the equal voltage. Followings arerespectively means which can solve such a drawback.

[0059] (Means 9)

[0060] A liquid crystal display device according to the presentinvention, for example, comprises;

[0061] a liquid crystal layer which is sandwiched between a pair ofsubstrates which face each other in an opposed manner,

[0062] a plurality of pixel regions, and

[0063] pixel electrodes and counter electrodes which are formed on eachpixel region on a liquid-crystal-layer-side surface of one substrate outof the pair of substrates, wherein

[0064] each pixel region includes a first pixel and a second pixelrespectively having the plurality of counter electrodes formed thereon,

[0065] the distance from one substrate to the counter electrodes at thefirst pixel is set longer than the distance at the second pixel, and

[0066] the distance between the plurality of counter electrodes in thepixel at the first pixel is set shorter than the distance at the secondpixel.

[0067] (Means 10)

[0068] A liquid crystal display device according to the presentinvention, for example, comprises;

[0069] a liquid crystal layer which is sandwiched between a pair ofsubstrates which face each other in an opposed manner,

[0070] a plurality of pixel regions, and

[0071] pixel electrodes and counter electrodes which are formed on eachpixel region on a liquid-crystal-layer-side surface of one substrate outof the pair of substrates, wherein

[0072] each pixel region includes a first pixel and a second pixelrespectively having the plurality of pixel electrodes formed thereon,

[0073] the distance from one substrate to the pixel electrodes at thefirst pixel is set longer than the distance at the second pixel, and

[0074] the distance between the plurality of pixel electrodes in thepixel at the first pixel is set shorter than the distance at the secondpixel.

[0075] (Means 11)

[0076] A liquid crystal display device according to the presentinvention, for example, comprises;

[0077] a liquid crystal layer which is sandwiched between a pair ofsubstrates which face each other in an opposed manner,

[0078] a plurality of pixel regions, and

[0079] pixel electrodes and counter electrodes which are formed on eachpixel region on a liquid-crystal-layer-side surface of one substrate outof the pair of substrates, wherein

[0080] each pixel region includes a first pixel and a second pixel whichdiffer in the distance from one substrate to the counter electrodes,

[0081] the distance from one substrate to the counter electrodes at thefirst pixel is set longer than the distance at the second pixel, and

[0082] the distance between the pixel electrodes and the counterelectrodes at the first pixel is set shorter than the distance at thesecond pixel.

[0083] (Means 12)

[0084] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of the means 11,characterized in that the pixel electrodes and the counter electrodesare constituted as separate layers.

[0085] (Means 13)

[0086] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of the means 11,characterized in that the pixel electrodes and the counter electrodesare constituted as the same layer.

[0087] (Means 14)

[0088] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of the means 9,characterized in that the counter electrodes are formed on an organicfilm.

[0089] (Means 15)

[0090] A liquid crystal display device according to the presentinvention is, for example, based on means 10, characterized in that thepixel electrodes are formed on an organic film.

[0091] (Means 16)

[0092] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of the means 13,characterized in that the pixel electrodes and the counter electrodesare formed on an organic film.

[0093] (Means 17)

[0094] A liquid crystal display device according to the presentinvention, for example, comprises;

[0095] a liquid crystal layer which is sandwiched between a pair ofsubstrates which face each other in an opposed manner,

[0096] a plurality of pixel regions, and

[0097] pixel electrodes and counter electrodes which are formed on eachpixel region on a liquid-crystal-layer-side surface of one substrate outof the pair of substrates, wherein

[0098] each pixel region includes a first pixel and a second pixel whichdiffer in the difference between the distance between one substrate andthe pixel electrodes and the distance between one substrate and thecounter electrodes,

[0099] the difference at the first pixel is smaller than the differenceat the second pixel,

[0100] the distance between one substrate and the pixel electrodes atthe first pixel is larger than the distance between one substrate andthe pixel electrodes at the second pixel, and

[0101] the distance between one substrate and the counter electrodes atthe first pixel is larger than the distance between one substrate andthe counter electrodes at the second pixel.

[0102] (Means 18)

[0103] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of the means 17,characterized in that the pixel electrodes and the counter electrodesare formed as different layers by way of an organic film.

[0104] (Means 19)

[0105] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of any one of themeans 14 to 16 or 18, characterized in that the organic film isconstituted of color filters.

[0106] (Means 20)

[0107] A liquid crystal display device according to the presentinvention is, for example, based on the constitution of any one of themeans 9 to 11 or 17, characterized in that the first pixel and thesecond pixel are arranged close to each other.

[0108] Further means according to the present invention will becomeapparent from the description of this specification and attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0109]FIG. 1 is a cross-sectional view showing one embodiment of aliquid crystal display device according to the present invention.

[0110]FIG. 2 is an overall equivalent circuit diagram showing oneembodiment of the liquid crystal display device according to the presentinvention.

[0111]FIG. 3 is a plan view showing one embodiment of a pixel of theliquid crystal display device according to the present invention.

[0112]FIG. 4 is a cross-sectional view taken along a line IV-IV shown inFIG. 3.

[0113]FIG. 5 is a cross-sectional view of another embodiment of theliquid crystal display device according to the present invention.

[0114]FIG. 6 is a cross-sectional view of another embodiment of theliquid crystal display device according to the present invention.

[0115]FIG. 7 is a cross-sectional view of another embodiment of theliquid crystal display device according to the present invention.

[0116]FIG. 8 is a cross-sectional view of another embodiment of theliquid crystal display device according to the present invention.

[0117]FIG. 9 is a cross-sectional view of another embodiment of theliquid crystal display device according to the present invention.

[0118]FIG. 10 is a cross-sectional view of another embodiment of theliquid crystal display device according to the present invention.

[0119]FIG. 11 is a plan view of another embodiment of the pixel of theliquid crystal display device according to the present invention.

[0120]FIG. 12 is a cross-sectional view taken along a line XII-XII shownin FIG. 11.

[0121]FIG. 13 is an explanatory view for explaining an advantageouseffect according to the present invention.

[0122]FIG. 14 is a cross-sectional view showing another embodiment ofthe liquid crystal display device according to the present invention.

[0123]FIG. 15 is a cross-sectional view showing another embodiment ofthe liquid crystal display device according to the present invention.

[0124]FIG. 16 is an explanatory view necessary for showing portions ofrespective pixels shown in FIG. 14 and FIG. 15.

[0125]FIG. 17 is a cross-sectional view showing another embodiment ofthe liquid crystal display device according to the present invention.

[0126]FIG. 18 is a cross-sectional view showing another embodiment ofthe liquid crystal display device according to the present invention.

[0127]FIG. 19 is a cross-sectional view showing another embodiment ofthe liquid crystal display device according to the present invention.

[0128]FIG. 20 is a cross-sectional view showing another embodiment ofthe liquid crystal display device according to the present invention.

[0129]FIG. 21 is a cross-sectional view showing another embodiment ofthe liquid crystal display device according to the present invention.

[0130]FIG. 22 is a cross-sectional view showing another embodiment ofthe liquid crystal display device according to the present invention.

[0131]FIG. 23 is an explanatory view showing the displacement of a B-Vcurve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0132] Preferred embodiments of a liquid crystal device according to thepresent invention are explained herein after in conjunction withattached drawings.

[0133] Embodiment 1

[0134] <Equivalent Circuit>

[0135]FIG. 2 is an overall equivalent circuit diagram showing oneembodiment of a liquid crystal display device according to the presentinvention. Although the drawing shows the equivalent circuit, it isdepicted corresponding to an actual geometrical arrangement.

[0136] In FIG. 2, a pair of transparent substrates SUB1, SUB2 which arearranged to face each other in an opposed manner by way of liquidcrystal are provided. The liquid crystal is sealed by a sealing memberSL which is also served for fixing the other transparent substrate SUB2to one transparent substrate SUB1.

[0137] On a liquid-crystal-side surface of the above-mentioned onetransparent substrate SUB1 which is surrounded by the sealing member SL,gate signal lines GL which are extended in the x direction and arearranged in parallel in the y direction and drain signal lines DL whichare extended in the y direction and are arranged in parallel in the xdirection are formed.

[0138] Regions which are surrounded by respective gate signal lines GLand respective drain signal lined DL constitute pixel regions and a massof these respective pixel regions in a matrix array constitutes a liquidcrystal display part AR.

[0139] Common counter voltage signal lines CL which run in the inside ofrespective pixel regions are formed on respective pixel regions whichare arranged in parallel in the x direction. These counter voltagesignal lines CL constitute signal lines for supplying signal voltageswhich become the reference with respect to video signals to counterelectrodes CT of respective pixel regions which will be explained later.

[0140] On each pixel region, a thin film transistor TFT which isoperated in response to scanning signals from one-side gate signal lineGL and a pixel electrode PX to which the video signals are supplied fromthe one-side drain signal line DL through the thin film transistor TFTare formed.

[0141] The pixel electrode PX generates an electric field between thepixel electrode PX and the counter electrode CT which is connected tothe counter voltage signal line CL and the light transmittance of theliquid crystal is controlled based on the electric field.

[0142] Respective ends of the gate signal lines GL are extended over thesealing member SL and the extended ends constitute terminals to whichoutput terminals of a vertical scanning driving circuit V are connected.Further, to input terminals of the vertical scanning driving circuit V,signals from a printed circuit board which is arranged outside a liquidcrystal display panel are inputted.

[0143] The vertical scanning driving circuit V is constituted of aplurality of semiconductor devices, wherein a plurality of gate signallines GL which are arranged close to each other are formed into a groupand one semiconductor device is allocated to every group.

[0144] In the same manner, respective ends of the drain signal lines DLare extended over the sealing member SL and the extended ends constituteterminals to which output terminals of a video signal driving circuit Heare connected. Further, to input terminals of the video signal drivingcircuit He, signals from the printed circuit board which is arrangedoutside the liquid crystal display panel are inputted.

[0145] The video signal driving circuit He is also constituted of aplurality of semiconductor devices, wherein a plurality of drain signallines DL which are arranged close to each other are formed into a groupand one semiconductor device is allocated to every group.

[0146] The counter voltage signal lines CL each of which is provided incommon with respect to respective pixel regions arranged in parallel inthe x direction have right-side end portions thereof in the drawingconnected in common and the connection line is extended over the sealingmember SL and the extended end constitutes a terminal CTM. A voltagewhich becomes the reference with respect to the video signals issupplied from this terminal CTM.

[0147] With respect to the above-mentioned respective gate signals linesGL, these gate signal lines GL is sequentially selected one by one inresponse to the video signal from the vertical scanning circuit V.

[0148] Further, the liquid crystal display device is configured suchthat the video signals are supplied to respective drain signal lines DLfrom the video signal driving circuit He in accordance with theselection timing of the gate signal lines GL.

[0149] <<Constitution of Pixels>>

[0150]FIG. 3 is a plan view showing the constitution of the pixel regionand FIG. 4 is a cross-sectional view taken along a line IV-IV of FIG. 3.

[0151] On the liquid-crystal-side surface of the transparent substrateSUB1, first of all, a pair of gate signal lines GL (one gate signal lineGL being not shown in the drawing) are formed such that the gate signallines GL are extended in the x direction and are arranged in parallel inthe y direction.

[0152] A pair of these gate signal lines GL surround the rectangularregion together with a pair of drain signal lines DL (one drain signalline DL being not shown in the drawing) as explained later and thisregion constitutes the pixel region.

[0153] Further, the counter voltage signal line CL which is arranged inparallel with the gate signal lines GL is formed in the region definedbetween respective gate signal lines GL.

[0154] On the surface of the transparent substrate SUB1 on which thegate signal lines GL and the counter voltage signal lines CL are formedin the above-mentioned manner, an insulation film GI which is made ofSiN, for example, is formed such that the insulation film GI also coversthe gate signal lines GL and the counter voltage signal lines CL.

[0155] The insulation film GI performs a function of an interlayerinsulation film with respect to the gate signal lines GL and the countervoltage signal lines CL in the region where the drain signal lines DLwhich will be explained later are formed, performs a function of a gateinsulation film in a region where a thin film transistor TFT which willbe explained later is formed, and performs a function of a dielectricfilm in a region where a capacitive element Cstg which will be explainedlater is formed.

[0156] Then, on a surface of the insulation film GI, a semiconductorlayer AS which is made of amorphous Si, for example, is formed such thatthe semiconductor layer AS is superposed on a portion of the gate signallines GL.

[0157] The semiconductor layer AS constitutes a portion of the thin filmtransistor TFT. That is, by forming a drain electrode SD1 and a sourceelectrode SD2 on an upper surface of the semiconductor layer AS, an MIStype transistor having an inverse staggered structure which uses aportion of the gate signal line GL as a gate electrode can be formed.

[0158] Here, the drain electrode SD1 and source electrode SD2 aresimultaneously formed along with the formation of the drain signal linesDL.

[0159] That is, the drain signal line DL which is extended in the ydirection is formed and a portion of the drain signal line DL isextended to an upper surface of the semiconductor layer AS so as to formthe drain electrode SD1, and the source electrode SD2 is formed in aspaced apart manner from the drain electrode SD1 by a length of channelof the thin film transistor TFT.

[0160] The source electrode SD2 is slightly extended from the surface ofthe semiconductor layer AS to an upper surface of the insulation film GIat the pixel region side thus forming a contact portion for providingthe connection of the source electrode SD2 with the pixel electrode PXwhich will be explained later.

[0161] Further, on an interface between the semiconductor layer AS andthe drain electrode SD1 and the source electrode SD2, a thin film dopedwith impurities of high concentration is formed and this layer functionsas a contact layer.

[0162] The contact layer may be formed such that, at the time of formingthe semiconductor layer AS, an impurity layer of high concentration ispreliminarily formed, and using patterns of the drain electrode SD1 andthe source electrode SD2 formed on an upper surface of the impuritylayer as masks, the impurity layer which is exposed from the drainelectrode SD1 and the source electrode SD2 are etched.

[0163] On a surface of the transparent substrate on which the thin filmtransistor TFT, the drain signal lines DL, the drain electrodes SD1 andthe source electrodes SD2 are formed in the above-mentioned manner, acolor filter FIL is formed.

[0164] The color filter FIL has a color which is different from a colorof other neighboring pixel region in the x direction and is common witha color of other neighboring pixel region in the y direction.

[0165] That is, the color filters FIL of a group of pixel regions whichare arranged in parallel in the y direction are formed of common resinmaterial layers containing the same pigment and these color filters areseparately formed from the color filters FIL formed of resin materiallayers which are formed in common with respect to other group of pixelregions which are arranged in parallel in the y direction at both sidesof the above-mentioned group of pixel regions and contain the pigment ofdifferent color.

[0166] In this case, the color filter FIL also plays a role of aprotective film which prevents the deterioration of characteristics ofthe thin film transistor TFT by avoiding the direct contact between thethin film transistor TFT and the liquid crystal.

[0167] The pixel electrode PX is formed on an upper surface of the colorfilter FIL. The pixel electrode PX is constituted of a group ofelectrodes formed of a plurality of (two pieces in this embodiment)which are extended in the y direction and are arranged in parallel inthe x direction, for example. These respective electrodes are connectedin common at portions which are disposed close to the thin filmtransistor TFT and are electrically connected with the contact portionof the source electrode SD2 of the thin film transistor TFT through acontact hole CH1 formed in the color filter FIL.

[0168] Then, on an upper surface of the color filter FIL on which thepixel electrode PX is formed in this manner, a flattening film OC whichis made of a resin material layer, for example, is formed such that theflattening film OC also covers the pixel electrode PX.

[0169] Further, the counter electrode CT is formed on an upper surfaceof the flattening film OC. The counter electrode CT is constituted of agroup of a plurality of electrodes (three pieces in this embodiment)which are extended in the y direction and are arranged in parallel inthe x direction.

[0170] In a plan view, the respective counter electrodes CT arepositioned such that the pixel electrode PX is arranged between thecounter electrode CT. That is, these counter electrodes CT arerespectively arranged at an equal interval in the order of the counterelectrode CT, the pixel electrode PX, the counter electrode CT, thepixel electrode PX and the counter electrode CT from the drain signalline DL at one side to the drain signal line DL at the other side.

[0171] Further, the counter electrodes CT which are constituted of agroup of electrodes in this manner are electrically connected with eachother at portions thereof which are superposed on the counter voltagesignal line CL and have portions thereof electrically connected with thecounter voltage signal line CL through contact holes CH2 which areformed in the flattening film OC and the color filter FIL as throughholes.

[0172] Here, among a group of respective counter electrodes CT, a pairof counter electrodes CT which are positioned at both sides, that is,the counter electrodes CT which are disposed adjacent to the drainsignal lines DL are formed such that their width is slightly larger thanthe width of other counter electrodes CT.

[0173] Such a constitution is adopted for facilitating the line ofelectric force from the drain signal line DL to be terminated to theneighboring counter electrode CT as well as for preventing the lines ofelectric force from the drain signal line DL from getting over thecounter electrode CT and being terminated to the pixel electrode PX.That is, when the lines of electric force are terminated to the pixelelectrode PX, this gives rise to noises.

[0174] Further, portions of the respective counter electrodes CT whichare electrically connected are superposed on portions of respectivepixel electrodes PX which are electrically connected by way of theflattening film OC which constitutes a layer disposed below therespective counter electrodes CT. Further, portions of respective pixelelectrodes PX which are electrically connected are superposed on thecounter voltage signal line CL by way of the color filter FIL and theinsulation film GI. Capacitive elements Cstg are formed at theserespective superposed portions.

[0175] These capacitive elements Cstg have a function of storing videosignals supplied to the pixel electrodes PX, for example, for arelatively long period.

[0176] On the upper surface of the transparent substrate SUB1 on whichthe counter electrodes CT are formed, an orientation film ORI1 is formedsuch that the orientation film ORI1 also covers the counter electrodesCT. The orientation film ORI1 is a film which directly comes intocontact with the liquid crystal and is provided for determining theinitial orientation direction of liquid crystal molecules by a rubbingformed on a surface thereof.

[0177] <<Relationship with other neighboring pixels>>

[0178]FIG. 1 is a view showing a cross section of respective pixelregions provided with the red color filter FIL (R), the green colorfilter FIL (G) and the blue color filter FIL (B) which are arrangedclose to each other. Although the pixel having two pixel electrodes PXand three counter electrodes CT is shown in FIG. 4, to simplify theexplanation, the pixel having one pixel electrode PX and two counterelectrodes CT is shown in FIG. 1.

[0179] In FIG. 1, first of all, the red color filter FIL (R), the greencolor filter FIL (G) and the blue color filter FIL (B) are formed withtheir layer thicknesses made different from each other. As mentionedpreviously, there may be a case that the layer thicknesses of respectivecolor filters are intentionally set to different values to attain thebalance of transmittance or color purity among respective color filtersFIL or a case in which the layer thickness is not made uniform over allcolor filters FIL due to the irregularities in manufacturing these colorfilters FIL.

[0180] Accordingly, the difference in layer thicknesses of respectivecolor filters FIL is reflected on the height of the flattening film OCformed on the respective color filters FIL from the surface of thetransparent substrate SUB1. That is, the height of the flattening filmOC is set high when the layer thickness of the color filter FIL is largeand is set low when the layer thickness of the color filter FIL issmall.

[0181] Although the flattening film OC is constituted of a resin filmformed by coating in this embodiment, it is difficult to make theflattening film OC completely flat in a literal meaning of the word. Forexample, in reality, even when the complete flattening is requested,this leads to the cumbersomeness of the manufacturing process.

[0182] Accordingly, with respect to the pixel having the color filterFIL of large layer thickness, the layer thickness of the liquid crystal(liquid crystal gap) becomes small, while with respect to the pixelhaving the color filter FIL of small layer thickness, the layerthickness of the liquid crystal becomes large.

[0183] Here, the liquid crystal is interposed between the transparentsubstrate SUB1 and the transparent substrate SUB which is arranged toface the transparent substrate SUB1 in an opposed manner and at leastthe color filters FIL are not formed on the liquid-crystal-side surfaceof the transparent substrate SUB2.

[0184] In this manner, in the pixel region having the liquid crystal ofsmall layer thickness, when it is necessary to make the liquid crystalobtain the fixed light transmittance in such a portion, a voltageapplied between the pixel electrode PX and the counter electrode CT mustbe increased, while in the pixel region having liquid crystal of largelayer thickness, the voltage which is applied between the pixelelectrode PX and the counter electrode CT must be decreased.

[0185] In other words, when the voltage applied between the pixelelectrode PX and the counter electrode CT is set uniform, the lighttransmittance of the liquid crystal fluctuates in response to the layerthickness of the color filter FIL.

[0186] To cope with such a drawback, in this embodiment, when the layerthickness of the color filters FIL is decreased in the descending orderof the red color filter FIL (R), the green color filter FIL (G) and theblue color filter FIL (B), for example, the film thickness of theflattening film OC which is superposed on these respective color filtersFIL are sequentially increased.

[0187] To explain in more detail, the film thickness of the flatteningfilm OC is set to satisfy the following formula (1);

[0188] 0<film thickness difference of interlayer insulation filmsbetween pixel regions

<film thickness difference of color filters between pixel regions  (1)

[0189] and

[0190] the relationship that as the thickness of the color filter FILcorresponding to the pixel is increased, the film thickness of theflattening film OC corresponding to the pixel is increased.

[0191] When material having the same viscosity as that of the materialof a conventional flattening film is used as the material of theflattening film OC, the coating is performed using spin coating. In thiscase, it is possible to set the film thickness to the above-mentionedrelationship by controlling the rotational speed of the spin to a propervalue. It is needless to say that a technique other than the spincoating can be used for forming the flattening film OC.

[0192] The liquid crystal display device having such a constitution canobviate the elevation of the driving voltage caused by the attenuationof the driving electric field due to the fact that the layer thicknessof the flattening film OC is thick and also can obviate the lowering ofthe driving voltage caused by the birefringence mode derived from thefact that the layer thickness of the liquid crystal is thick.

[0193] Since these advantageous effects work in a complementary manner,the irregularities of the driving voltage for driving the liquid crystalcan be suppressed.

[0194] Further, as another embodiment, the brightness irregularities canbe further suppressed by making the liquid crystal display devicesatisfy a following formula (2).

[0195] ¼×film thickness of color filter FIL between pixels

[0196] <film thickness difference of flattening film OC between pixels,

<¾×film thickness difference of color filter FIL between pixels  (2)

[0197] Further, in adopting the above-mentioned constitution, when thefilm thickness of the flattening film OC is excessively large, thesurface becomes flattened and hence, it is preferable to make the liquidcrystal device satisfy a following formula (3).

[0198] film thickness of flattening film OC

<{fraction (3/2)}times film thickness of thickest color filter FIL  (3)

[0199] Further, when the film thickness of the flattening film OC isexcessively small, the stepped-portion narrowing effect is reduced andhence, it is preferable to make the liquid crystal display devicesatisfy a following formula (4).

[0200] ¼times film thickness of thinnest color filter FIL

[0201] <film thickness of flattening film OC

<{fraction (3/2)}times film thickness of thickest color filter FIL  (4)

[0202] Embodiment 2

[0203]FIG. 5 is a cross-sectional view of another embodiment of a liquidcrystal display device according to the present invention andcorresponds to FIG. 1.

[0204] The constitution which differs from the constitution shown inFIG. 1 is that respective counter electrodes CT which are positioned atboth sides of the drain signal line DL are connected such that thecounter electrodes CT also cover the drain signal lines DL.

[0205] Due to such a constitution, lines of electric force from thedrain signal lines DL which become a cause of noises are terminated tothe corresponding counter electrodes CT and hence, it is possible tosufficiently prevent the lines of electric force from being terminatedto the pixel electrodes PX arranged close to the counter electrodes CT.

[0206] Embodiment 3

[0207]FIG. 6 is a cross-sectional view of another embodiment of a liquidcrystal display device according to the present invention andcorresponds to FIG. 1.

[0208] The constitution which differs from the constitution shown inFIG. 1 is that the counter electrodes CT are formed over the wholeregions of respective pixel regions and are also connected with theneighboring counter electrodes CT each other.

[0209] Here, as material of the counter electrodes CT, transparentmaterial such as ITO (Indium Tin Oxide), for example, is used.

[0210] Due to such a constitution, there is no fear of disconnection ofthe counter electrodes CT and the total resistance value can bedrastically reduced.

[0211] Embodiment 4

[0212]FIG. 7 is a cross-sectional view of another embodiment of a liquidcrystal display device according to the present invention andcorresponds to FIG. 5.

[0213] The constitution which differs from the constitution shown inFIG. 5 is that the pixel electrodes PX are formed as layers below theflattening film OC and the counter electrodes CT are formed as layersabove the flattening film OC.

[0214] Also in this embodiment, respective counter electrodes CT whichare positioned at both sides of the drain signal line DL are connectedwith each other such that the counter electrodes CT also cover the drainsignal lines DL.

[0215] Since stepped portions formed by the flattening film OC aresmaller than stepped portions formed by the color filters FIL, thecounter electrodes CT formed on the stepped portions are formed on theflattening film OC.

[0216] Embodiment 5

[0217]FIG. 8 is a cross-sectional view of another embodiment of a liquidcrystal display device according to the present invention andcorresponds to FIG. 1.

[0218] The constitution which differs from the constitution shown inFIG. 1 is that the pixel electrodes PX are formed as layers above theflattening film OC and the counter electrodes CT are formed as layersbelow the flattening film OC. That is, this embodiment is characterizedby changing over the layers constituting respective electrodes.

[0219] Due to such a constitution, the same advantageous effects can beobtained.

[0220] Embodiment 6

[0221]FIG. 9 is a cross-sectional view of another embodiment of a liquidcrystal display device according to the present invention andcorresponds to FIG. 6, for example.

[0222] The constitution which differs from the constitution shown inFIG. 6 is that spacers which define a gap between the transparentsubstrate SUB1 and the transparent substrate SUB are constituted ofso-called support columns SUP which are formed on theliquid-crystal-side surface of the transparent substrate SUB byselectively etching resin material using a photolithography technique,for example.

[0223] To apply the present invention to the liquid crystal displaydevice, it is necessary to accurately determine the layer thickness ofthe liquid crystal. The irregularities of height of the liquid crystalcan be minimized with the provision of the stoppers which areconstituted of the support columns SUP.

[0224] As locations where these spacers are formed, the spacers arepositioned such that distal ends thereof are brought into contact withthe color filters FIL having the largest film thickness. The filmthickness of the flattening film OC formed on the color filters FILhaving the largest film thickness is small and hence, the irregularitiesof the film thickness is small whereby the uniformity of the gap formedby the spacers can be ensured.

[0225] Although the irregularities of the height is increased when theheight of the spacers per se is increased, by bringing the spacers intocontact with the color filters FIL having the largest film thickness,the height of the spacers can be made small so that the irregularitiesof the height are reduced whereby the uniformity of the gap formed bythe spacers can be ensured.

[0226] Embodiment 7

[0227]FIG. 10 is a cross-sectional view of another embodiment of aliquid crystal display device according to the present invention andcorresponds to FIG. 9.

[0228] The constitution which differs from the constitution shown inFIG. 9 is that the spacers constituted of the support columns SUP areformed on the liquid-crystal-side surface of the transparent substrateSUB1.

[0229] Embodiment 8

[0230]FIG. 11 is a plan view showing another embodiment of the pixel ofthe liquid crystal display device according to the present invention andFIG. 12 is a cross-sectional view taken along a line XII-XII in FIG. 11.

[0231] Different from the liquid crystal display devices of theabove-mentioned embodiments, in the liquid crystal display device shownin FIG. 11, the color filters FIL are formed on the transparentsubstrate SUB side and the flattening film OC is formed such that theflattening film OC also covers the color filters FIL.

[0232] At respective pixel regions on the liquid-crystal-LC-side surfaceof the transparent substrate SUB1, the pixel electrodes PX are formed onthe gate insulation films GI, and the counter electrodes CT are formedon an upper surface of a laminated body which covers the pixelelectrodes and consists of a protective film PSV1 made of SiN film and aprotective film PSV2 made of organic material, for example.

[0233] Further, with respect to the counter electrode CT which isarranged close to the drain signal line DL out of these counterelectrodes CT, such a counter electrode CT is formed such that thecounter electrode CT covers the drain signal line DL and is connected tothe other counter electrode CT which is arranged close to the drainsignal line DL in other neighboring pixel region which is disposed closeto the pixel region of the counter electrode CT while sandwiching thedrain signal line DL between the pixel region and the other neighboringpixel region.

[0234] Then, assuming the film thicknesses of respective protectivefilms PSV1, PSV2 on the pixel electrode PX as d₃, d₂ and the filmthicknesses of respective protective films PSV1, PSV2 on a regionbetween the counter electrode CT and the pixel electrode PX as d₃′, d₂′,when the relationship among these layer thicknesses satisfies afollowing formula (5), the influence of the film thickness d₄ of thepixel electrodes PX can be attenuated.

d ₃ ≡d ₃ ′, d ₂ <d ₂ ′<d ₂ +d ₄  (5)

[0235] Accordingly, the relationship between the layer thickness (liquidcrystal gap) d₁ of the liquid crystal on the pixel electrode PX and theliquid crystal gap d₁′ on the region between the counter electrode CTand the pixel electrode PX can be expressed by a following formula (6).

d ₁ ≡d ₁′ (here, d ₁ ≦d ₁′)  (6)

[0236] The reason that the condition d₁≦d₁′ is set is that it isdifficult to manufacture the liquid crystal display device under thecondition of d₁>d₁′ in actual manufacturing.

[0237] Due to such a constitution, the concentration of the electricfield due to the liquid crystal gap in respective pixels can beattenuated.

[0238] It is preferable that the approximation in the formulae (5), (6)is equal to or less than 100 nm.

[0239] Further, the electric field which is generated between thecounter electrode CT and the pixel electrode PX is weakened by theprotective films PSV1, PSV2 interposed between respective electrodes.

[0240] Due to the relationship expressed by the above-mentioned formula(5), the electric field applied to the protective films PSV1, PSV2 onthe pixel electrode PX becomes smaller than the electric field appliedto the protective films PSV1, PSV2 in the region between the counterelectrode CT and the pixel electrode PX so that the electric field isliable to be applied to the liquid crystal at the gap d₁ portion.

[0241]FIG. 13(a), (b), (c) are views for showing the thickness x of theprotective film on the pixel electrode PX and the change of electricfield in the liquid crystal corresponding to the thickness x. As can beclearly understood from these drawings, corresponding to the decrease ofthe thickness x of the protective film, the electric field on the pixelelectrode PX is increased.

[0242] Accordingly, in this method which adopts the lateral electricfield driving, it is possible to form the uniform electric field betweenthe counter electrode CT and the pixel electrode PX in each pixelregion.

[0243] To explain the conventional constitution, the layer thickness ofthe protective films are set such that d₃≡d₃′, d₂≡d₂′ and the electricfield receives the influence of the film thickness d₄ of the pixelelectrode PX so that the relationship between the liquid crystal gap d₁on the pixel electrode PX and the liquid crystal gap d₁′ on the regionbetween the counter electrode CT and the pixel electrode PX is expressedas d₁+d₄≡d₁′.

[0244] In the liquid crystal of the birefringence mode used in thelateral electric field driving, the wider the liquid crystal gap, thevoltage for driving the liquid crystal is lowered. Accordingly, theliquid crystal at the liquid crystal gap d₁′ portion can be driveneasily at the low voltage compared to the liquid crystal at the liquidcrystal gap d₁ portion.

[0245] Further, the shortest length X₁ between the counter electrode CTwhich passes along the surface of the protective film PSV2 and the pixelelectrode PX at the liquid crystal gap d₁ portion is longer than theshortest length X₁′ between the counter electrode CT which passes alongthe surface of the protective film PSV2 and the pixel electrode PX atthe liquid crystal gap d₁′ portion and the above-mentioned relationshipd₃≡d₃′, d₂≡d₂′ is established. Accordingly, based on an formula E=A×V/x(E: electric field, V: voltage applied to counter electrode and pixelelectrode, x: shortest length between counter electrode which passesalong surface of protective film PSV2 and pixel electrode, A: positiveproportion constant), the electric field applied to the liquid crystalgap d₁′ portion is remarkably increased compared to the electric fieldapplied to the liquid crystal gap d₁ portion so that the electric fieldof the pixel region in the vicinity of the pixel electrode PX becomesweak thus giving rise to the lowering of the light transmittance.

[0246] Embodiment 9

[0247]FIG. 14 is a cross-sectional view of the pixel at a portion of aliquid crystal display device according to the present invention andFIG. 15 is a cross-sectional view of the pixel at another portion of theliquid crystal display device. For example, in a liquid crystal displaypart AR of the liquid crystal display device shown in FIG. 16, a crosssection of the pixel at the portion X in the drawing is shown in FIG. 14and a cross section of the pixel at the portion Y in the drawing isshown in FIG. 15. Here, the cross-sectional portion of the pixel issimilar to that of FIG. 11.

[0248] To compare the constitutions described in FIG. 14 and FIG. 15,they differ in the film thickness of the protective film PSV1 at theportion of the liquid crystal display part AR. That is, while the filmthickness of the protective film PSV1 in FIG. 14 is set to X₃, the filmthickness of the protective film PSV1 in FIG. 15 is set to y₃ (<x₃).

[0249] In forming the protective film PSV1, the protective film PSV1 isnot formed uniformly over the entire region of the liquid crystaldisplay part AR and this implies that there exists the irregularities offilm thickness.

[0250] Here, while the film thickness of the protective film PSV2 formedon the upper surface of the protective film PSV1 is set to x₂ in FIG.14, the film thickness of the protective film PSV2 is set to Y₂ (≡x₂) inFIG. 15. That is, these film thicknesses are assumed to be substantiallyequal.

[0251] Here, the electric field applied to the region between thecounter electrode CT and the pixel electrode PX is increased at the thinportion of the protective film PSV1 since the liquid crystal gaps x₁, y₁have the relationship of x₁≡y₁ (substantially equal to the diameter ofbeads contained in the liquid crystal).

[0252] Accordingly, in this embodiment, to make the electric fielduniform over the respective pixel regions, the film thicknessses of theprotective film PSV2 are set to x₂<Y₂. This setting is made tocompensate for the relationship X₃>y₃ of respective film thicknesses ofthe protective film PSV1.

[0253] In view of the above, a following formula (7) is established.

x ₂ +X ₃ ≡Y ₂ +Y ₃ , X ₃ >y ₃ , X ₂ <Y ₂  (7)

[0254] In the above-mentioned respective embodiments, the pixelelectrodes PX are formed as layers below the protective film PSV and thecounter electrodes CT are formed as layers above the protective filmPSV. However, it is needless to say that the pixel electrodes PX and thecounter electrodes CT may be formed in a reverse manner. That is, thepixel electrodes PX are formed as layers above the protective film andthe counter electrodes CT are formed as layers below the protective filmPSV.

[0255] Embodiment 10

[0256] When the distance from the substrate SUB1 to the liquid crystallayer differs, the thickness of the liquid crystal layer differs asshown in FIG. 17 as an example. In the lateral electric field, thedriving voltage depends on the thickness of the liquid crystal layer.That is, the thicker the liquid crystal layer, the same brightness canbe obtained with the lower voltage. Assuming that the distance betweenthe electrodes is all equal in FIG. 17, the pixel in the region Xassumes the higher driving voltage than the pixel in the region Y. Thisphenomenon is explained in conjunction with FIG. 22. In FIG. 22, the B-Vcurves are shown, wherein the voltage V is taken on the axis ofabscissas and the brightness B is taken on an axis of ordinates. Aindicates the B-V curve in the region X in FIG. 17 and B indicates theB-V curve in the region Y in FIG. 17. The curve A takes the gentler B-Vcurve than the curve B. Accordingly, these curves A, B differ in thegray scale displayed with respect to a certain voltage.

[0257] Accordingly, in this embodiment, as shown in FIG. 17, thedistance between the electrodes is configured to have the particularconstitution. The distance from the substrate SUB1 to the counterelectrode CT at the pixel corresponding to the region X is longer thansuch a distance at the pixel corresponding to the region Y. In FIG. 17,the distance from the substrate SUB1 to the counter electrode CT assumesthe relationship d10 >d20. Although a plurality of counter electrodes CTmay be provided for each pixel, in FIG. 17, two counter electrodes CTare provided for each pixel. Assuming the distance between the counterelectrodes CT at the pixel corresponding to the region X as L3 and sucha distance at the pixel corresponding to the region Y as L6, therelationship L6>L3 is satisfied. That is, this embodiment ischaracterized in that the distance between the counter electrodes CT atthe pixel corresponding to the region X is shorter than the distancebetween the counter electrodes CT at the pixel corresponding to theregion Y.

[0258] Due to such a constitution, it is possible to make theintensities of electric field which are respectively formed in theregion X and the region Y when the equal voltage is applied to becomemore uniform so that it is possible to make the inclinations of the B-Vcurves of both regions close to each other. Accordingly, thedisplacement of the gray scale can be reduced.

[0259] Further, assume the distance between the pixel electrode PX andthe counter electrode CT at the pixel corresponding to the region X asL1 and L2 and the distance between the pixel electrode PX and thecounter electrode CT at the pixel corresponding to the region Y as L4and L5. Here, by making these distances satisfy the relationship L4,L6>L1, L2 or at least one of the relationships L4>L1 or L4>L2 and L5>L1or L5>L2, it is possible to make the intensities of electric fieldrespectively generated in the region X and the region Y when the equalvoltages applied to become more uniform so that the inclinations of theB-V curves of both regions can be made closer to each other.Accordingly, the displacement of the gray scale can be reduced.

[0260] In FIG. 17, as an example, the protective film PSV1 is made of aninorganic film and the protective film PSV2 is made of an organic film,for example. In FIG. 17, the counter electrodes CT are arranged over thevideo signal lines DL by way of the organic films PSV2. Accordingly,while suppressing the parasitic capacitance between the video signallines DL and the counter electrodes CT, it is possible to shield theelectric field leaked from the video signal lines DL. To sufficientlyobtain only the leaked electric field shielding effect by lowering theparasitic capacitance, it is preferable that the protective film PSV2has some thickness. From this point of view, it is preferable that theprotective film PSV2 is made of the organic film. However, the organicfilm has a serious drawback that the film thickness irregularitiesintrinsic to a coating device is liable to be generated. However, byadopting the concept of this embodiment, the influence of the differenceof the film thickness to the B-V curves can be obviated so that it ispossible to sufficiently obtain only the leaked electric field shieldingeffect.

[0261] Embodiment 11

[0262]FIG. 18 shows another constitutional example which can realize theimprovement effect obtained by the embodiment 10. This embodimentdiffers from the embodiment 10 with respect to a point that the numberof counter electrodes CT and the number of pixel electrodes PX areincreased as shown in FIG. 17. This embodiment also differs from theembodiment 10 with respect to a point that both of the counterelectrodes CT and the pixel electrodes PX are formed over the protectivefilm PSV2. Constitutions other than the above-mentioned constitutionsare as same as the corresponding constitutions in FIG. 17 and bringabout the similar advantageous effect as the advantageous effectsobtained by the corresponding constitutions in FIG. 17.

[0263] The distances from the substrate SUB1 to the pixel electrodes PXare set to d30>d31, wherein the distance at the region X is made largerthan the distance at the region Y. Here, the distance between the pixelelectrodes PX is set to satisfy the relationship L8>L7 wherein L7indicates the distance at the region X and L8 indicates the distance atthe region Y. Accordingly, due to such a constitution, in the samemanner as the embodiment 10, it is possible to make the intensities ofelectric field which are respectively formed in the region X and theregion Y when the equal voltage is applied to become more uniform sothat the inclinations of the B-V curves of both regions can be madecloser to each other. Accordingly, the displacement of the gray scalecan be reduced.

[0264] Embodiment 12

[0265] The reduction of the displacement of the gray scale which hasbeen explained in conjunction with the embodiment 10 is also effectivewith respect to the constitution which provides the difference in thethickness of the liquid crystal layer between the neighboring pixels.

[0266]FIG. 19 shows the constitution in which the thickness of theliquid crystal layer differs between the neighboring pixels. As theprotective film PSV2 shown in FIG. 17, color filters FIL are provided.FIG. 19 shows the cross-sectional structure of a plurality of pixels inthe direction that the gate signal lines GL are extended. In thedrawing, the color of the color filter FIL assumes any one of values R,G, B for every pixel thus constituting the three primary colors. Theboundaries of the color filters are positioned on the drain lines DL. Inthe liquid crystal display device, it is necessary to realize the givencolor. Accordingly, it is difficult to make the color filters have thecompletely equal thickness among colors. Accordingly, as shown in FIG.19, the liquid crystal display device is configured such that thedistance from the substrate SUB1 to the liquid crystal layer differsevery pixel corresponding to the color filter FIL so that the thicknessof the liquid crystal layer also differs every pixel.

[0267] To reduce the displacement of the gray scale using such astructure, it is advantageous to adopt at least one of following means.

[0268] (1) With respect to respective pixels, the longer the distancefrom the surface of the substrate SUB1 to the counter electrode CT, thedistance between the counter electrodes CT is made shorter.

[0269] (2) With respect to respective pixels, the longer the distancefrom the surface of the substrate SUB1 to the counter electrode CT,distance between the counter electrode CT and the pixel electrode PX ismade shorter.

[0270] This embodiment can reduce the displacement of the gray scale byadopting both of the above-mentioned means (1), (2).

[0271] The order of the film thickness of R, G, B in this embodiment isset for an explanation purpose and it is not always necessary to adoptthis order. That is, the order can be suitably determined in conformitywith the characteristics of materials of respective colors used forforming the color filters FIL. The essential point is that at least oneof the above-mentioned means (1) or (2) is satisfied.

[0272] Embodiment 13

[0273]FIG. 20 is a constitutional example in which the counterelectrodes CT and the pixel electrodes PX in FIG. 19 are arranged overthe color filters FIL. This constitution can also realize the reductionof the displacement of the gray scale by adopting at least one of themeans (1), (2) of the embodiment 12. In this embodiment, both means (1)(2) are adopted thus enhancing the reduction of the displacement of thegray scale.

[0274] Embodiment 14

[0275]FIG. 21 shows a schematic cross-sectional structure of a pluralityof neighboring pixels in this embodiment. The difference between thestructure shown in FIG. 21 and the structure shown in FIG. 19 lies inthat an overcoat OC is formed over the color filters FIL. Differencealso lies in that the counter electrodes CT are formed over the overcoatOC and the pixel electrodes PX are arranged below the overcoat OC.

[0276] The constitution of this embodiment also can realize thereduction of the displacement of the gray scale by adopting at least oneof means (1), (2) of the embodiment 12.

[0277] Further, this embodiment is also characterized by therelationship of the film thickness of the overcoat OC with respect tothe color filters FIL. That is, the overcoat OC is thin at the pixelhaving the thick color filter FIL and the overcoat OC is thick at thepixel having the thin color filter FIL. Due to such a constitution, thedifference of thickness of liquid crystal layer among pixels havingdifferent colors can be reduced more compared to the state in which theovercoat OC is not provided. Due to such a constitution, thedisplacement of the gray scale can be reduced.

[0278] The overcoat OC having the relationship shown in FIG. 21 as anexample can be realized by coating overcoat material in a liquid formwhose viscosity is suitably determined on the color filters FIL, thenleaving the overcoat material for several tens of seconds and,thereafter, heating the overcoat material OC together with the substrateSUB1.

[0279] In this embodiment, by adopting the structural feature which canreduce the difference of thickness of the liquid crystal layer and bothof means (1), (2) of the embodiment 12, the displacement of the grayscale can be further reduced.

[0280] Embodiment 15

[0281]FIG. 22 corresponds to FIG. 21. The constitution shown in FIG. 22differs from the constitution shown in FIG. 21 with respect to a pointthat the pixel electrodes PX are also formed over the overcoat OC.

[0282] The constitution of this embodiment also can reduce thedisplacement of the gray scale by adopting at least one of means (1),(2) of the embodiment 12.

[0283] The above-mentioned respective embodiments may be used in asingle form or in combination. This is because that the advantageouseffects of respective embodiments can be obtained in a single form or incombination.

[0284] As can be clearly understood from the above description, theliquid crystal display device according to the present invention canenhance the display quality.

What is claimed is:
 1. A liquid crystal display device beingcharacterized in that: a pair of electrodes which constitute an upperlayer and a lower layer with respect to an interlayer insulation filmare formed as different layers at respective pixel regions on aliquid-crystal-side surface of one substrate out of respectivesubstrates which are arranged to face each other in an opposed manner byway of liquid crystal, at two pixel regions which are selected from therespective pixel regions, the height of background layers on which theelectrodes which constitute the lower layers with respect to theinterlayer insulation films differs with respect to a surface of onesubstrate, and the film thickness of the interlayer insulation film isset small with respect to the high background layer out of therespective background layers which differ in height and is set largewith respect to the low background layer out of the respectivebackground layers which differ in height.
 2. A liquid crystal displaydevice being characterized in that: a pair of electrodes whichconstitute an upper layer and a lower layer with respect to aninterlayer insulation film are formed on at least color filters asdifferent layers at respective pixel regions on a liquid-crystal-sidesurface of one substrate out of respective substrates which are arrangedto face each other in an opposed manner by way of liquid crystal fromthe one substrate side, at two pixel regions which are selected from therespective pixel regions and on which two color filters of differentcolors are formed, the height of surfaces of the color filters differswith respect to a surface of one substrate, and the film thickness ofthe interlayer insulation film is set to satisfy a following formula(1). 0<film thickness difference of the interlayer insulation filmbetween pixel regions <film thickness difference of the color filtersbetween pixel regions  (1)
 3. A liquid crystal display device beingcharacterized in that: a pair of electrodes which constitute an upperlayer and a lower layer with respect to an interlayer insulation filmare formed on at least color filters as different layers at respectivepixel regions on a liquid-crystal-side surface of one substrate out ofrespective substrates which are arranged to face each other in anopposed manner by way of liquid crystal from the one substrate side, attwo pixel regions which are selected from the respective pixel regionsand on which two color filters of different colors are formed, theheight of surfaces of the color filters differs with respect to asurface of one substrate, and the film thickness of the interlayerinsulation film is set to satisfy a following formula (2). ¼×filmthickness difference of color filter between pixel regions <filmthickness difference of interlayer insulation film between pixelregions, <¾×film thickness difference of color filter between pixelregions  (2)
 4. A liquid crystal display device according to claim 2 or3, wherein the film thickness of the interlayer insulation film is setto satisfy a following formula (3). film thickness of interlayerinsulation film <{fraction (3/2)}times film thickness of thickest colorfilter  (3)
 5. A liquid crystal display device according to claim 2 or3, wherein the film thickness of the interlayer insulation film is setto satisfy a following formula (4). ¼ of film thickness of thinnestcolor filter <film thickness of interlayer insulation film <{fraction(3/2)} times film thickness of thickest color filter  (4)
 6. A liquidcrystal display device being characterized in that: a pair of electrodeswhich constitute an upper layer and a lower layer with respect to aninterlayer insulation film are formed as different layers at respectivepixel regions on a liquid-crystal-side surface of one substrate out ofrespective substrates which are arranged to face each other in anopposed manner by way of liquid crystal, at the respective pixelregions, the height of background layers on which the electrodes whichconstitute the lower layers with respect to the interlayer insulationfilms are formed differs with respect to a surface of one substrate, andthe film thickness of the interlayer insulation film is set small withrespect to the high background layer out of the respective backgroundlayers which differ in height and is set large with respect to the lowbackground layer out of the respective background layers which differ inheight.
 7. A liquid crystal display device being characterized in that:at respective pixel regions on a liquid-crystal-side surface of onesubstrate out of respective substrates which are arranged to face eachother in an opposed manner by way of liquid crystal, a pair ofelectrodes are formed by way of a protective film which is formed bysequentially laminating a first protective film and a second protectivefilm, the respective electrodes are arranged in a spaced-apart manner ina plan view so as to generate an electric field between electrodes, therelationship between the film thicknesses d₃, d₂ of the first protectivefilm and the second protective film on the electrode arranged as a layerbelow the protective film and the film thicknesses d₃′, d₂′ of the firstprotective film and the second protective film on a region between thepair of electrodes satisfies a following formula (5) d₃ ≡d ₃ ′, d ₂ <d ₂′<d ₂ +d ₄  (5), and the relationship between the layer thickness d₁ ofliquid crystal on the electrode arranged below the protective film andthe layer thickness d₁′ of the liquid crystal on the region between thepair of electrodes satisfies a following formula (6). d ₁ ≡d ₁′ (where,d₁ <d ₁′)  (6)
 8. A liquid crystal display device being characterized inthat: at respective pixel regions formed on a liquid-crystal-sidesurface of one substrate out of respective substrates which are arrangedto face each other in an opposed manner by way of liquid crystal, a pairof electrodes are formed by way of a protective film which is formed bysequentially laminating a first protective film and a second protectivefilm, the respective electrodes are arranged in a spaced-apart manner ina plan view so as to generate an electric field between the electrodes,and in two selected pixel regions, assuming the film thickness of thefirst protective film in one pixel region as x₃, the film thickness ofthe second protective film in one pixel region as x₂, the film thicknessof the first protective film in the other pixel region as y₃ and thefilm thickness of the second protective film in the other pixel regionas y₂, a following formula (7) is established. x ₂ +x ₃ ≡y ₂ +y ₃ , x₃ >y ₃ , x ₂ <y ₂  (7)
 9. A liquid crystal display device comprising; aliquid crystal layer which is sandwiched between a pair of substrateswhich face each other in an opposed manner, a plurality of pixelregions, and pixel electrodes and counter electrodes which are formed oneach pixel region on a liquid-crystal-layer-side surface of onesubstrate out of the pair of substrates, wherein each pixel regionincludes a first pixel and a second pixel respectively having theplurality of counter electrodes formed thereon, the distance from onesubstrate to the counter electrodes at the first pixel is set longerthan the distance at the second pixel, and the distance between theplurality of counter electrodes in the pixel at the first pixel is setshorter than the distance at the second pixel.
 10. A liquid crystaldisplay device comprising; a liquid crystal layer which is sandwichedbetween a pair of substrates which face each other in an opposed manner,a plurality of pixel regions, and pixel electrodes and counterelectrodes which are formed on each pixel region on aliquid-crystal-layer-side surface of one substrate out of the pair ofsubstrates, wherein each pixel region includes a first pixel and asecond pixel respectively having the plurality of pixel electrodesformed thereon, the distance from one substrate to the pixel electrodesat the first pixel is set longer than the distance at the second pixel,and the distance between the plurality of pixel electrodes in the pixelat the first pixel is set shorter than the distance at the second pixel.11. A liquid crystal display device comprising; a liquid crystal layerwhich is sandwiched between a pair of substrates which face each otherin an opposed manner, a plurality of pixel regions, and pixel electrodesand counter electrodes which are formed on each pixel region on aliquid-crystal-layer-side surface of one substrate out of the pair ofsubstrates, wherein each pixel region includes a first pixel and asecond pixel which differ in the distance from one substrate to thecounter electrodes, the distance from one substrate to the counterelectrodes at the first pixel is set longer than the distance at thesecond pixel, and the distance between the pixel electrodes and thecounter electrodes at the first pixel is set shorter than the distanceat the second pixel.
 12. A liquid crystal display device according toclaim 11, wherein the pixel electrodes and the counter electrodes areconstituted as separate layers.
 13. A liquid crystal display deviceaccording to claim 11, wherein the pixel electrodes and the counterelectrodes are constituted as the same layer.
 14. A liquid crystaldisplay device according to claim 9, wherein the counter electrodes areformed on an organic film.
 15. A liquid crystal display device accordingto claim 10, wherein the pixel electrodes are formed on an organic film.16. A liquid crystal display device according to claim 13, wherein thepixel electrodes and the counter electrodes are formed on an organicfilm.
 17. A liquid crystal display device comprising; a liquid crystallayer which is sandwiched between a pair of substrates which face eachother in an opposed manner, a plurality of pixel regions, and pixelelectrodes and counter electrodes which are formed on each pixel regionon a liquid-crystal-layer-side surface of one substrate out of the pairof substrates, wherein each pixel region includes a first pixel and asecond pixel which differ in the difference between the distance betweenone substrate and the pixel electrodes and the distance between onesubstrate and the counter electrodes, the difference at the first pixelis smaller than the difference at the second pixel, the distance betweenone substrate and the pixel electrodes at the first pixel is larger thanthe distance between one substrate and the pixel electrodes at thesecond pixel, and the distance between one substrate and the counterelectrodes at the first pixel is larger than the distance between onesubstrate and the counter electrodes at the second pixel.
 18. A liquidcrystal display device according to claim 17, wherein the pixelelectrodes and the counter electrodes are formed as different layers byway of an organic film.
 19. A liquid crystal display device according toclaim 14, wherein the organic film is constituted of color filters. 20.A liquid crystal display device according to claim 15, wherein theorganic film is constituted of color filters.
 21. A liquid crystaldisplay device according to claim 16, wherein the organic film isconstituted of color filters.
 22. A liquid crystal display deviceaccording to claim 18, wherein the organic film is constituted of colorfilters.
 23. A liquid crystal display device according to claim 9,wherein the first pixel and the second pixel are arranged close to eachother.
 24. A liquid crystal display device according to claim 10,wherein the first pixel and the second pixel are arranged close to eachother.
 25. A liquid crystal display device according to claim 11,wherein the first pixel and the second pixel are arranged close to eachother.
 26. A liquid crystal display device according to claim 17,wherein the first pixel and the second pixel are arranged close to eachother.